Interface trouble with datetimepicker

I have some troubles using the datetimepicker on an en_US machine in the program generation area https://lohrothek.dev.lohro.de/manage/broadcasts/create-from-rules. There are format issues with yyyy-mm-dd (US) vs dd.mm.yyyy (DE)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information